This application relates to a shutoff valve placed on a connecting discharge line downstream of a compressor operating in a tandem compressor arrangement.
Refrigerant systems typically include a compressor delivering a compressed refrigerant from a compressor discharge port to a condenser, and then passing the refrigerant from the condenser to an expansion device, an evaporator, and then back to the compressor suction port. The load demand on the refrigerant cycle may vary. At times, there may be a need for a higher system cooling capacity and hence higher compressed refrigerant flow, and at other times, a lower cooling capacity and consequently lower refrigerant flow.
To provide continuous efficient supply of the desired amount of compressed refrigerant, some larger refrigerant systems utilize tandem compressors. In such systems, two compressors may simultaneously deliver a compressed refrigerant to a downstream heat exchanger, such as a condenser. Typically, fluid lines communicate with the discharge ports of the two compressors, and are merged into a single discharge line that sends refrigerant to the condenser. The system suction line is split in similar fashion into individual suction lines connecting to the suction port of each tandem compressor.
A control for such a tandem compressor system will operate one, or both of the compressors depending on system load. In situations where only one of the compressors is operational, the refrigerant can leak from a discharge line to suction line through the shutdown compressor. While the compressors are typically provided with a discharge check valve within the compressor shell, such check valves typically are not tight enough to prevent such leakage. Further, under high pressure differential, such check valves may distort and become even less fluid-tight, or malfunction. Thus, the prior art tandem compressors, even the ones with check valves within the compressor shell can have substantial leakage losses and subsequent system performance degradation.